Field of the Invention
The present invention relates to a radiation imaging apparatus, a radiation imaging system, and an irradiation start detection method.
Description of the Related Art
There is known a radiation imaging apparatus that electrically captures an optical image formed by radiation such as X-rays. The method of the radiation imaging apparatus can be largely divided into a direct method in which radiation is directly converted into an electrical signal and an indirect method in which radiation is converted into light by a scintillator and the light is converted into an electrical signal. In either method, the radiation image capturing operation needs to be performed in synchronization with the start of radiation irradiation. As a method of synchronization, there is a method in which a synchronization signal is transmitted from a control device of a radiation source to the radiation imaging apparatus and a method in which the radiation imaging apparatus detects the radiation with which it has been irradiated. Japanese Patent Laid-Open No. 2014-23957 discloses a radiation imaging apparatus that detects the start of radiation irradiation based on an electrical signal arising from charges generated in a sensor unit.
In a method in which the radiation imaging apparatus detects the radiation with which it has been irradiated to detect the start of radiation irradiation, an error can occur if large noise is included in a signal that has sensitivity to the emitted radiation.